Method for combating certain virus infection

ABSTRACT

A METHOD OF PREVENTING OR TREATING HERPES VIRUS INFECTIONS IN ANIMALS BY ADMINSTERING PHOSPHONOACETIC ACID OR ITS SALTS.

United States Patent Patented Oct. 23, 1973 DETAILED DESCRIPTION 3,767,795 METHOD FOR COMBATING CERTAIN ExamPle 1 05 h B d d w R Phosphonoacetic acid and its disodium salt are active ep B11131; eic er, 9 u a 1 a against herpes dermatiitis when applied topically to mice ggiilesnggizgbgrtlygrlle, IlL, asslgno s f0 Abbott 5 infected cutaneously with herp s type 2 virus. The acid is No Drawing? l ned Feb. 25 1971- Ser. No. 119 056 at wncentrafi? as as 01%; a 2% 99' Int CL A61k 27/50 centration of the salt being required. Herpes dermatitis 2 2 Claims in mice has the disadvantage that since the virus is es lo pecially neurotropic in this species, the disease rapidly progresses from localized skin lesions to central nervous ABSTRACT OF THE DISCLOSURE system involvement with paralysis and death. There is A method of preventing o treating herpes virus i f good correlation in mice between lesion development and tions in animals by administering phosphonoacetic acid Subsequent death so that a Compound which reduces the or its salts. number of deaths generally also decreases the number and severity of skin lesions. Consequently, the criterion used for determining activity of a compound in vivo BACKGROUND OF THE INVENTION against herpes dermatitis is reduction in the number of Herpes virus infections, though ommon, are difii ult to deaths. Activity was demonstrated when the compound prevent or treat because of the la k of ff ti ,d A was administered intraperitoneally or orally, but high effective anti-herpes drug could be u ed i th t t t dosages are required, the therapeutic ratio is low, and the or prevention of herpes dermatitis, herpes genitalis, herpes eflicacy is less than that obtained with topical treatment. keratitis, and herpes encephalitis. Herpes virus i th Representative in vivo results against herpes dematitis single, most important infectious agent causing blindness are as follows:

Percent Mg.lkg. reduction Compound Route per day Days in deaths Phosphonoaeetic acid Topical, 0.5% 5 100 Disodium salt Topical, 2% 5 70-100 Phosphonoaeetie d LP 7 50 Do- O 7 50 Disodium saltn "do 5 90 N O'rE.Non-treated control animals all died.

in the United States. Although herpes dermatitis is a very common though minor disease, better control of herpes dermatitiscould result in fewer cases of herpetic keratitis. The basic treatment presently available for herpetic keratitis is idoxuridine, and no specific drug is available for herpes dermatitis.

SUMMARY OF THE INVENTION The compounds are active against herpes viruses, particularly herpes simplex virus types 1 and 2 and vaccinia virus. The compounds are administered either as the acid or as the alkali metal salts particularly the mono, di, or trisodium salt or the calcium salt. The activity against herpes virus is restricted to phosphonoacetic acid and its group, or ethylene or propylene group, for example, are required, with an unsubstituted methylene group connecting them. Compounds with a substituted methylene group, or ethylene or propylene group, for example, are inactive. Phosphonoacetic acid and its salts inhibit replication of herpes simplex virus types 1 and 2 and vaccinia virus in tissue culture. The compounds are preferably administered topically but can be given orally or intraperitoneally (i.p.). Exemplifying the activity in vivo, phosphonoacetic acid is active topically against herpes keratitis in the infected rabbit eye and both phosphonoacetic acid and its sodium and calcium salts are active against herpes dermatitis when applied topically to mice infected with herpes type 2 virus. The disodium compound causes a 60100% increase in survival of mice infected with herpes simplex.

Example 2 The effectiveness of the disodium salt of phosphonuacetic acid against herpes simplex infection in mice was determined in the following manner. Mice were infected with herpes simplex virus, type 2 and treated as indicated with the disodium salt two hours post infection and each of the five days thereafter. Virus inoculation was accomplished by plucking the fur from the flank and back of anesthetized mice and placing a drop (0.05 ml.) of herpes virus on the surface of the plucked skin. Using a needle, the skin of the mouse was pricked through the drop of virus. The mice utilized for control purposes were not treated in any manner.

Percent Concentration Route survivors Condition of survivors Virus controls 0 2% Topical"--- 100 70% no herpetic lesions, 30%

paralyzed, with herpetic bantk.

800 rngJl-rg Oral 100 n0 herpetic lesions, 20%

paralyzed, with herpetie bands.

1,000 mgJkg do 100 Do.

1,200 rug/kg 100 no herpetlc lesions. 10%

paralyzed, with herpetic bands.

Do. 60 D0.

From an examination of the results, it is apparent that the disodium salt of phosphonoacetic acid is active when administered topically at a concentration of two percent and orally from 800-1400 milligrams per kilogram (mg./ kg.). When administered at 1600 mg./kg. daily for five days, the compound was toxic to mice in that 4 out of 10 animals died. At this dosage level, one additional mouse was paralyzed but showed no herpetic lesions. The condition of survivors of the full length of treatment is indicated. It should be noted that paralysis is due to the virus and not the drug.

3 Example 3 The antiviral activity against vaccinia virus of the compounds of this invention was evaluated in mice. The effectiveness of the compounds was determined by their ability to suppress the formation of tail lesions using the method of Boyle, J. J. et al., Evaluation of Antiviral Compounds by Suppression of Tail Lesions in Vaccinia Infected Mice, Antimicrobial Agents and Chemotherapy, pp. 536-539 (1966). Ten to twelve gram mice were inoculated intravenously approximately 2 centimeters from the base of the tail with 0.05 milliliter undilute vaccinia virus. All of the compounds were prepared in tragacanth and 0.5 milliliter administered subcutaneously in the nape of the neck beginning 3 hours post infection and continuing once daily for 7 days. On the eighth day post infection, the mouse tails were swabbed with 0.25% methylene blue and the number of lesions counted. The control compound was methisazone.

Dosage, Number of lesions Avg. 25 Percent Compound mgJkg. per mouse (N) {N reduction Normal control 0, 0, 0, 0, 0, 0, 0, 0, ()6

Virus control 14, 30, 2a, 20, 20. 9, "Z'IIIIIIIIII Methisazone 200 3, 2, 2, 3, O, 5, 3,222, 1. 4 65 Phosphonoacetic 100 3, 0, 1, 6, 6, 7, 6, 6:4, 1. 9 52 acid. 6

Example 4 Herpes keratitis in rabbits Post-infection day 1--R every hour for 8 hours Post-infection day 2R every hour for '8 hours Post-infection day 3---R every hour for 4 hours Total=24 treatments.

Medication was applied as a 0.1% solution of phosphonoacetic acid.

The eyes of the rabbits were examined for corneal lesions from post-infection days 4 through 10. One drop of sodium fluorescein dye was added to each eye which was then examined with a Woods ultraviolet lamp. The severity of the corneal lesions were rated as follows:

The compounds of the present invention can be dispensed in compositions comprising the active ingredients and excipients. The amount of active ingredient to be given daily depends on many factors such as the age and size of the warm-blooded animals and the severity of infection. A dosage of from to 1400 mg./kg. of body weight is suitable and may be in a form to be administered one or more times per day or in smaller forms for multidaily or, other more frequent administrations. When applied topically, an ointment containing from 0.2 to 10% active ingredient is suitable. The compounds can be formulated for use in a conventional manner well-known in the art, utilizing pharmaceutical excipients such as lactose, starch, magnesium stearate, glyceryl mono or distearate, talc or the like.

What is claimed is:

1. A method for treating virus infections selected from the group consisting of herpes dermatitis, herpes genitalis, herpes keratitis, and herpes encephalitis in an animal which comprises administering to an animal so infected an effective amount for combatting said virus infection of phosphonoacetic acid or an alkali metal salt thereof.

2. A method for treating viral infections caused by vaccinia virus in an animal which comprises administering to an animal so infected an effective amount for combatting vaccinia virus phosphonoacetic acid or an alkali metal salt thereof.

References Cited Antibotic News, vol. 5, No. 9, pp. 1 and 3, October 1968.

Stock et al., Cancer Research, vol. 20, No. 5, part 2, pp. 193, 194 and 342 (No. 21041) (June 1960).

Cancer Research, vol. 21, No. 8, part 2, pp. 377, 378, and 451 (No. 26626) (September 1961).

Cancer Research, vol. 24, No. 2, part 2, pp. 211, 212, 227 and 378 (No. 49971) (February 1964).

JEROME D. GOLDBERG, Primary Examiner UNITED S T A TES PATENT CERTIFICATE OF CORRECTIQN Patent No. 3, 767, 795 Dated October 23, 1973 Inventor(s) Joseph Bernard Schleicher and William R. Roderick It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

0 0 LI In Column 1 please delete HO-C--CH- P(OH) and In Column 1, line 57, please delete the first "group" and substitute "salts".

Signed and sealed this 17th day of September 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents RM 69) qscoMM-oc scan-pew "-5. GOVIINIINT PRINTING OFIICI 2 I!" D-Iq-ll 

